scholarly journals Etiopathogenesis of Insulin Autoimmunity

2012 ◽  
Vol 2012 ◽  
pp. 1-20
Author(s):  
Norio Kanatsuna ◽  
George K. Papadopoulos ◽  
Antonis K. Moustakas ◽  
Åke Lenmark

Autoimmunity against pancreatic islet beta cells is strongly associated with proinsulin, insulin, or both. The insulin autoreactivity is particularly pronounced in children with young age at onset of type 1 diabetes. Possible mechanisms for (pro)insulin autoimmunity may involve beta-cell destruction resulting in proinsulin peptide presentation on HLA-DR-DQ Class II molecules in pancreatic draining lymphnodes. Recent data on proinsulin peptide binding to type 1 diabetes-associated HLA-DQ2 and -DQ8 is reviewed and illustrated by molecular modeling. The importance of the cellular immune reaction involving cytotoxic CD8-positive T cells to kill beta cells through Class I MHC is discussed along with speculations of the possible role of B lymphocytes in presenting the proinsulin autoantigen over and over again through insulin-carrying insulin autoantibodies. In contrast to autoantibodies against other islet autoantigens such as GAD65, IA-2, and ZnT8 transporters, it has not been possible yet to standardize the insulin autoantibody test. As islet autoantibodies predict type 1 diabetes, it is imperative to clarify the mechanisms of insulin autoimmunity.

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Jeffrey Babad ◽  
Riyasat Ali ◽  
Jennifer Schloss ◽  
Teresa P. DiLorenzo

Type 1 diabetes (T1D) is an autoimmune disease characterized by T cell-mediated destruction of the pancreatic islet beta cells. Multiple genetic loci contribute to disease susceptibility in humans, with the most responsible locus being the major histocompatibility complex (MHC). Certain MHC alleles are predisposing, including the common HLA-A∗02:01. After the MHC, the locus conferring the strongest susceptibility to T1D is the regulatory region of the insulin gene, and alleles associated with reduced thymic insulin expression are predisposing. Mice express two insulin genes,Ins1andIns2. While both are expressed in beta cells, onlyIns2is expressed in the thymus. We have developed an HLA-A∗02:01-transgenic NOD-based T1D model that is heterozygous for a functionalIns2gene. These mice exhibit reduced thymic insulin expression and accelerated disease in both genders. Immune cell populations are not grossly altered, and the mice exhibit typical signs of islet autoimmunity, including CD8 T cell responses to beta cell peptides also targeted in HLA-A∗02:01-positive type 1 diabetes patients. This model should find utility as a tool to uncover the mechanisms underlying the association between reduced thymic insulin expression and T1D in humans and aid in preclinical studies to evaluate insulin-targeted immunotherapies for the disease.


2008 ◽  
Vol 52 (2) ◽  
pp. 156-165 ◽  
Author(s):  
Pierre Pirot ◽  
Alessandra K. Cardozo ◽  
Décio L. Eizirik

Type 1 diabetes mellitus (T1D) is characterized by severe insulin deficiency resulting from chronic and progressive destruction of pancreatic beta-cells by the immune system. The triggering of autoimmunity against the beta-cells is probably caused by environmental agent(s) acting in the context of a predisposing genetic background. Once activated, the immune cells invade the islets and mediate their deleterious effects on beta-cells via mechanisms such as Fas/FasL, perforin/granzyme, reactive oxygen and nitrogen species and pro-inflammatory cytokines. Binding of cytokines to their receptors on the beta-cells activates MAP-kinases and the transcription factors STAT-1 and NFkappa-B, provoking functional impairment, endoplasmic reticulum stress and ultimately apoptosis. This review discusses the potential mediators and mechanisms leading to beta-cell destruction in T1D.


2021 ◽  
Vol 12 ◽  
Author(s):  
Saurabh Vig ◽  
Joost M. Lambooij ◽  
Arnaud Zaldumbide ◽  
Bruno Guigas

Beta-cell destruction in type 1 diabetes (T1D) results from the combined effect of inflammation and recurrent autoimmunity. In response to inflammatory signals, beta-cells engage adaptive mechanisms where the endoplasmic reticulum (ER) and mitochondria act in concert to restore cellular homeostasis. In the recent years it has become clear that this adaptive phase may trigger the development of autoimmunity by the generation of autoantigens recognized by autoreactive CD8 T cells. The participation of the ER stress and the unfolded protein response to the increased visibility of beta-cells to the immune system has been largely described. However, the role of the other cellular organelles, and in particular the mitochondria that are central mediator for beta-cell survival and function, remains poorly investigated. In this review we will dissect the crosstalk between the ER and mitochondria in the context of T1D, highlighting the key role played by this interaction in beta-cell dysfunctions and immune activation, especially through regulation of calcium homeostasis, oxidative stress and generation of mitochondrial-derived factors.


Diabetes Care ◽  
2003 ◽  
Vol 26 (5) ◽  
pp. 1640-1641 ◽  
Author(s):  
T. Nakamura ◽  
S. Nagasaka ◽  
I. Kusaka ◽  
T. Yatagai ◽  
J. Yang ◽  
...  

1999 ◽  
Vol 26 (2-3) ◽  
pp. 117-127
Author(s):  
Jinko Graham ◽  
Ingrid Kockum ◽  
Carani B. Sanjeevi ◽  
Mona Landin-Olsson ◽  
Lennarth Nyström ◽  
...  

2021 ◽  
pp. 1-9
Author(s):  
Sherifa A. Hamed ◽  
Ali F. ElHadad ◽  
Amira M. Oseily

<b><i>Background:</i></b> Vestibular system is critical for maintaining balance and learning complex tasks. This study aimed to determine the frequencies, types, and predictors of vestibular dysfunctions (VDs) in children with type 1 diabetes (T1D) using videonystagmography (VNG). <b><i>Patients and Methods:</i></b> This study included 65 patients (children with T1D = 40; controls = 25). The patients underwent VNG. <b><i>Results:</i></b> Patients (boys = 15; girls = 25) had a mean age of 14.05 ± 1.82 years and duration of illness of 6.30 ± 2.84 years. The majority had frequent attacks of diabetic ketoacidosis (DKA) (65%) and hypoglycemia (40%). Dizziness was reported in 20%. VNG abnormalities were reported in 70% (<i>n</i> = 28), of them 71.43 and 28.57% had central and peripheral VDs, respectively. Dizziness was associated with peripheral VD. Compared to patients without VDs, those with VDs were older and had earlier age at onset and longer duration of diabetes (&#x3e;5 years), higher levels of HbA1c (&#x3e;7%), higher frequencies of DKA and hypoglycemic attacks, comorbid medical conditions, and diabetic complications. Multiple logistic regression analysis showed that presence of VNG abnormalities (VDs) was independently correlated with diabetes duration &#x3e;5 years (odds ratio [OR] = 4.52 [95% confidence interval [CI] = 3.55–7.04], <i>p</i> = 0.001), HbA1c% levels &#x3e;7% (OR = 3.42 [95% CI = 2.84–5.75], <i>p</i> = 0.001), and presence of hypoglycemic attacks (OR = 4.65 [95% CI = 2.85–7.55]). <b><i>Conclusions:</i></b> -VDs are prevalent in children with T1D and correlated with the duration and severity of diabetes and the occurrence of hypoglycemic attacks. Therefore, optimizing glycemic control and prevention and treatment of diabetic complications and comorbidities are important. Multidisciplinary follow-ups are required for early detection and management of diabetic VDs.


Author(s):  
Basma Haris ◽  
Ahmed Abdellatief ◽  
Houda Afyouni ◽  
Tasneem Abdel-Karim ◽  
Shayma Mohammed ◽  
...  

Abstract Objectives Children with antibody positive type 1 diabetes mellitus (type 1 diabetes) are at an increased risk of developing celiac disease (CD) which suggests a common autoimmune basis with both high-risk human lymphocyte antigen (HLA) and non-HLA factors playing a role in the pathophysiology. We aim to describe the prevalence, immune profile, and clinical characteristics of children with CD who have type 1 diabetes mellitus in Qatar. Methods All children (aged 0–18 years) attending a regional diabetes clinic with antibody positive type 1 diabetes were screened for CD. Measurement of tissue transglutaminase IgA and IgG as well as anti-endomysial antibody, was done, clinical details about the birth history, family history of diabetes and CD, age of onset, and ethnicity were collected. Results Out of the 1,325 children with antibody positive type 1 diabetes, 54 were identified to have CD on screening and then confirmed on small bowel biopsy. The prevalence of CD in the type 1 diabetes childhood population in Qatar is 4.07%. CD and type 1 diabetes were more prevalent in the Qatari children (n=32) as compared to non-Qatari (n=22) and occurred mostly in the age group 6–10 years. The most common type 1 diabetes antibodies in children with CD were glutamic acid decarboxylase and insulin autoantibody. Twelve subjects were asymptomatic for CD symptoms and picked up only on screening. Conclusions The prevalence of CD in children with type 1 diabetes in Qatar is comparable to reports from around the world. Many children were asymptomatic and thus routine screening is recommended.


Diabetologia ◽  
2008 ◽  
Vol 51 (7) ◽  
pp. 1192-1201 ◽  
Author(s):  
C. Roisin-Bouffay ◽  
R. Castellano ◽  
R. Valéro ◽  
L. Chasson ◽  
F. Galland ◽  
...  

1999 ◽  
pp. 272-278 ◽  
Author(s):  
F Dotta ◽  
S Dionisi ◽  
V Viglietta ◽  
C Tiberti ◽  
MC Matteoli ◽  
...  

The target molecules of the T-cell response in type 1 diabetes, despite their pathogenic importance, remain largely uncharacterized, especially in humans. Interestingly, molecules such as insulin and glutamic acid decarboxylase (GAD) have been shown to be a target not only of autoantibodies, but also of autoreactive T-lymphocytes both in man and in the non-obese diabetic (NOD) mouse. In the present study we aimed to determine the existence of a specific T-cell response towards the insulinoma-associated protein 2 (IA-2) islet tyrosine phosphatase, a recently identified autoantigen which is the target of autoantibodies strongly associated with diabetes development. Human recombinant IA-2 produced in Escherichia coli, was tested for its reactivity with peripheral blood lymphocytes obtained from 16 newly diagnosed type 1 diabetic patients and from 25 normal controls, 15 of whom were HLA-DR-matched. A T-cell proliferation assay was performed in triplicate employing freshly isolated cells in the absence or in the presence of the antigen to be tested (at two different concentrations: 2 microg/ml and 10 microg/ml). A specific T-cell proliferation (defined as a stimulation index (S.I.) >/=3) was observed against IA-2 used at a concentration of 10 microg/ml (but not of 2 microg/ml) in 8/16 diabetic patients, in 1/15 HLA-DR-matched control subjects (P<0.01 by Fisher exact test) and in 0/10 of the remaining normal individuals. A statistically significant difference (P<0.003 by Mann-Whitney U test) was also observed in S.I. values between patients (3.1+/-1.4) and HLA-DR-matched controls (1.7+/-0.54) employing IA-2 at a concentration of 10 microg/ml. However, when IA-2 was used at a concentration of 2 microg/ml, the difference in S. I. between patients (1.65+/-0.8) and controls (1.0+/-0.3) did not reach statistical significance. In conclusion, these data show the presence of a specific, dose-dependent T-lymphocyte response against the IA-2 islet tyrosine phosphatase at the onset of type 1 diabetes. Consequently, this molecule appears to be a target not only at the B-lymphocyte but also at the T-lymphocyte level, reinforcing the potential pathogenic role of this autoantigen in the islet destructive process.


2019 ◽  
Author(s):  
Colleen M. Elso ◽  
Nicholas A. Scott ◽  
Lina Mariana ◽  
Emma I. Masterman ◽  
Andrew P.R. Sutherland ◽  
...  

AbstractType 1, or autoimmune, diabetes is caused by the T-cell mediated destruction of the insulin-producing pancreatic beta cells. Non-obese diabetic (NOD) mice spontaneously develop autoimmune diabetes akin to human type 1 diabetes. For this reason, the NOD mouse has been the preeminent murine model for human type 1 diabetes research for several decades. However, humanized mouse models are highly sought after because they offer both the experimental tractability of a mouse model and the clinical relevance of human-based research. Autoimmune T-cell responses against insulin, and its precursor proinsulin, play central roles in the autoimmune responses against pancreatic beta cells in both humans and NOD mice. As a first step towards developing a murine model of the human autoimmune response against pancreatic beta cells we set out to replace the murine insulin 1 gene (Ins1) with the human insulin gene (INS) using CRISPR/Cas9. Here we describe a NOD mouse strain that expresses human insulin in place of murine insulin 1, referred to as HuPI. HuPI mice express human insulin, and C-peptide, in their serum and pancreata and have normal glucose tolerance. Compared with wild type NOD mice, the incidence of diabetes is much lower in HuPI mice. Only 15-20% of HuPI mice developed diabetes after 300 days, compared to more than 60% of unmodified NOD mice. Immune-cell infiltration into the pancreatic islets of HuPI mice was not detectable at 100 days but was clearly evident by 300 days. This work highlights the feasibility of using CRISPR/Cas9 to create mouse models of human diseases that express proteins pivotal to the human disease. Furthermore, it reveals that even subtle changes in proinsulin protect NOD mice from diabetes.


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